FIELD OF THE INVENTION
The invention relates to a smart card module and a smart card including a smart card module.
Smart card modules usually include a carrier on which a semiconductor chip is bonded or fastened in some other way. The carrier may be a thin printed circuit board or a plastic sheet having a side remote from the chip on which an electrically conductive layer made of copper or the like is laminated. The layer is structured to form individual contact areas which can be tapped by a card reader. Instead of the laminated carrier sheet, the semiconductor chip can also be fitted to a metallic lead frame, with or without an intermediate carrier, into which the individual contact areas are stamped. The form and size of the contact areas usually depend on specific standard specifications such as, for example, ISO Standard 7816. In conventional smart card modules, electrical contact is made between the semiconductor chip and the contact areas with the aid of bonding wires which are routed from contact-making points of the semiconductor chip to terminal points of the contact areas. As an alternative, the semiconductor chip may be applied by using flip-chip technology.
In order to protect the chip and the connections to the contact areas, a layer of epoxy resin, thermosetting plastic or the like is applied over the chip and the connection points. The finished smart card module is finally implanted in a card carrier of a smart card.
Such smart card modules are disclosed, for example, in German Patent DE 44 24 396 C2, German Patent DE 195 32 755 C1, German Patent DE 26 59 573 C2, U.S. Pat. No. 4,803,542, as well as European Patent Application 0 071 311 A2.
Particularly the smart card module disclosed in German Patent DE 195 32 755 C1, from which the invention of the instant application proceeds, shows a metallic lead frame with a semiconductor chip mounted in flip-chip technology. The lead frame has a three-dimensional structure produced through etching.
German Patent DE 195 12 191 C1 describes specific materials for producing lead frames of smart card modules. Patent Abstracts of Japan Publication No. 06342794 A describes a semiconductor package in which a passivation layer partially covers an electrode surface between a chip surface and a housing.
The smart card modules constructed in the manner described above generally have a component height of at least 500 to 600 .mu.m. It has not been possible to date to realize smaller component heights. Moreover, due to the relatively large component height of the smart card modules, the card carrier can only be very thin in the region of the module in order not to exceed the predetermined total thickness of the smart card. Sunken locations therefore appear on the card surface in the region of the smart card module.